Welcome to the new Spudis Lunar Resources Blog!

Thank you for checking out my new blog. I am setting up this blog to discuss controversial and/or “political” topics for which my current “Once and Future Moon” blog at the Smithsonian’s Air and Space magazine is inappropriate. I plan to post here on occasion to discuss a variety of topics, most related to our return to the Moon and our lack of progress thereof.

Comments are open. Initially, all are welcome and no one is banned, although I will not hesitate to do so if you are abusive, obscene or exceedingly repetitious. If a topic has been covered or a point has been made, move on. Additional comments on points already made will be deleted. I welcome critical, thoughtful feedback.

4 Responses to Welcome to the new Spudis Lunar Resources Blog!

Thank you for your new post. I am sure it will get a lot of traffic. I believe I sent you my Robotic Lunar project memo about 7 or 8 years ago. If not, I will send to if asked.

For the past two years, I have been working with the solarhigh.org group updating the 1979 Boeing Reference System. I have an August 2012 informal report on our work I can also send if it is relevant.

Although using lunar resources to build these things has interested me for more than 30 years, we did not employ that option for now, nor did we use such things as tethers, air-breathing or laser propulsion. Our results indicate that a simple update is likely to close the business case, using 2012 technology. Later developments can only improve the case. Our finding needs confirmation.

Now a pair of questions:

1. What is the likelihood that badly needed rare earth elements and lithium deposits are present in the lunar regolith, perhaps in high concentration in some craters?

2. Would transshipment to GSO or Earth via L-2 make sense using lunar water to produce propellants?

What is the likelihood that badly needed rare earth elements and lithium deposits are present in the lunar regolith, perhaps in high concentration in some craters?

These elements are present on the Moon, but typically in low concentration. The chemical component called “KREEP” (for potassium, rare earth elements, and phosphorus) is fairly widespread on the western near side and sometimes, highly concentrated in a few small areas. None of these deposits approach the concentrations of REE found in terrestrial deposits that are considered economic. We might find enough thorium in these areas on the Moon to fuel thorium reactors, however.

Would transshipment to GSO or Earth via L-2 make sense using lunar water to produce propellants?

I think so, although in the resource processing architecture I mentioned above, we used low lunar orbit as a staging node to export lunar water to cislunar. I think that we should probably keep this material in the form of water for easy transport and storage, cracking it into its component gases only when we are ready to use them as propellant.

When we begin to produce propellants in space from water we would be wise to also have rocket engines that operate at, or close to, 8:1 MR. This is to avoid having to stockpile, or discard, up to 3.5 kg of oxygen from every 9 kg of water. Current LOx/LH engines operate at 5.5:1 or 6:1 MR (O:H). A few people in space cannot consume the amount of oxygen remaining from water produced cryogenic propellants for engines in use today. Either that or we some other parallel activity that is oxygen intensive.

I have read that the ideal MR for a LOX-hydrogen engine is 4:1, leaving half the fuel unburned. Supposedly, this increases the total Isp. But I am less concerned about what to do with any excess oxygen than I am in setting up a sustained presence in cislunar. If we can find a use for “excess” oxygen, fine. If not, we can discard it. But we need to get a foothold on the Moon first.